This invention relates to a method of the production of a Pb-containing, copper oxide-type superconductor.
Known Pb-containing, copper oxide-type superconductors include, for example, Pb.sub.2 Sr.sub.2 Ca.sub.1-x Y.sub.x Cu.sub.3 O.sub.y (generally called 2213-phase superconductor), Pb.sub.1-x Cu.sub.x Sr.sub.2 Ca.sub.1-y Y.sub.y Cu.sub.2 O.sub.z (1212-phase), (Pb,Bi).sub.2 (Sr.sub.1-x La.sub.x).sub.2 CuO.sub.y (2201-phase superconductor) and (Pb.sub.1-x Cu.sub.x)(Sr.sub.1-y La.sub.y).sub.2 CuO.sub.z (1201-phase superconductor). These superconductors have been hitherto produced by a method including a solid-phase reaction in which a blend of solid raw materials is sintered at a high temperature.
The solid phase reaction method, however, has the following problems:
(1) Extensive pulverization is required in order to obtain a homogeneous blend of solid raw materials. This is disadvantageous from economic point of view. PA1 (2) A high sintering temperature is required. This is disadvantageous from economic point of view. Further, when the superconductor is formed into a composite body, a high sintering temperature will cause interfacial reaction between the oxide superconductor layer and a substrate, such as a coil or a wire, on which the layer is to be supported. Additionally, the kind of the substrate to be used should be limited to one which can withstand the high sintering temperature. PA1 (3) The superconductor has a crystal size of as high as several tens micron meters, so that a dense, homogeneous superconductor having an improved critical current density Jc cannot be obtained.